Emerson PR6423/002-031 Eddy Current Sensor Precision Shaft Vibration Monitoring

Emerson PR6423/002-031 (part of the EPRO series) is a high-performance 8mm eddy current proximity sensor engineered for non-contact measurement of shaft displacement, vibration, and position in the most demanding industrial environments. As a cornerstone of modern machinery protection systems, this sensor delivers the accuracy and reliability required to safeguard steam turbines, gas turbines, compressors, and pumps against catastrophic failure.

What is the Emerson PR6423/002-031?

The PR6423/002-031 is a variable reluctance eddy current sensor designed to detect the position of a conductive target without physical contact . It operates on the principle of electromagnetic induction: a high-frequency signal is generated in the sensor coil, and as a conductive (ferromagnetic) target approaches, eddy currents are induced, altering the impedance of the coil. This change is precisely proportional to the gap distance, allowing for micron-level measurement accuracy .

This specific model features an integral sensitivity factor (ISF) of 8 V/mm (±5%), making it a direct, factory-calibrated solution that eliminates the need for field calibration . It is typically paired with an EPRO proximitor (such as the CON021, CON031, or CON041) to demodulate the signal into a standard -2V to -18V DC output for integration with monitoring systems like the Emerson CSI 6500, AMS 6500, and MMS 6000 series .

Key Technical Specifications (Specs)

Understanding the precise specifications of the PR6423/002-031 is critical for proper system design and integration.

Manufacturer: Emerson (EPRO)

Model Number: PR6423/002-031 

Sensor Type: Non-Contact Eddy Current Proximity Sensor 

Probe Diameter: 8 mm 

Integral Sensitivity Factor (ISF): 8 V/mm (±5%) 

Linear Range: 2 mm (typical operating window) 

Initial Air Gap: 0.5 mm minimum 

Frequency Response: 0 – 10 kHz (-3dB point) 

Operating Temperature: -40°C to +125°C (-40°F to +257°F) 

Mounting Thread: M18 x 1.5 

Cable: Integral 5-meter cable (standard), extendable without signal loss 

Target Material Compatibility: Ferromagnetic steels (e.g., 4140, 416 stainless) 

Vibration & Shock Resistance: Robust construction for extreme industrial use 

The PR6423/002-031 is typically the first component in a measurement chain. To form a complete monitoring solution, it is used with:

Proximitors: CON021, CON031, CON041 (for signal conditioning) .

Monitoring Modules: A6110 (Vibration Monitor), A6210 (Position Monitor), MMS6110, MMS6210 .

Cables and Accessories: Extension cables and junction boxes for remote installations.

For reliability engineers and instrumentation professionals, the Emerson PR6423/002-031 represents the gold standard in eddy current sensing technology. Its robust design, factory-calibrated precision, and seamless integration with API 670-compliant protection systems provide the confidence needed to operate critical machinery safely and efficiently.